In psychology and cognitive science, cognitive biases are systematic patterns of deviation from norm and/or rationality in judgment. They are often studied in psychology, sociology and behavioral economics.
A memory bias is a cognitive bias that either enhances or impairs the recall of a memory (either the chances that the memory will be recalled at all, or the amount of time it takes for it to be recalled, or both), or that alters the content of a reported memory.
Explanations include information-processing rules (i.e., mental shortcuts), called heuristics, that the brain uses to produce decisions or judgments. Biases have a variety of forms and appear as cognitive ("cold") bias, such as mental noise, or motivational ("hot") bias, such as when beliefs are distorted by wishful thinking. Both effects can be present at the same time.
There are also controversies over some of these biases as to whether they count as useless or irrational, or whether they result in useful attitudes or behavior. For example, when getting to know others, people tend to ask leading questions which seem biased towards confirming their assumptions about the person. However, this kind of confirmation bias has also been argued to be an example of social skill; a way to establish a connection with the other person.
Although this research overwhelmingly involves human subjects, some studies have found bias in non-human animals as well. For example, loss aversion has been shown in monkeys and hyperbolic discounting has been observed in rats, pigeons, and monkeys.
Organization of cognitive biases Although the reality of these biases is confirmed by reproducible research, there are often controversies about how to classify these biases or how to explain them. Several theoretical causes are known for some cognitive biases, which provides a classification of biases by their common generative mechanism (such as noisy information-processing). Gerd Gigerenzer has criticized the framing of cognitive biases as errors in judgment, and favors interpreting them as arising from rational deviations from logical thought. This list is organized based on the task-based classification proposed by . This classification defines 6 tasks, namely estimation, decision, hypothesis assessment, causal attribution, recall, and opinion reporting. The biases are further loosely classified into 5 sub-categories or "flavors":
Association: a connection between different pieces of information Baseline: comparing something to a perceived standard or starting point Inertia: the reluctance to change something that is already in place Outcome: how well something aligns with an expected or hoped-for result Self-perspective: influenced by one's own personal point of view
Estimation In estimation or judgement tasks, people are asked to assess the value of a quantity.
Association Aesthetic–usability effect: A tendency for people to perceive attractive things as more usable.Kurosu, M., & Kashimura, K. (1995). Apparent usability vs. inherent usability: Experimental analysis on the determinants of the apparent usability. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (pp. 292–293). ACM. https://doi.org/10.1145/223904.223966 Attribute substitution: Occurs when a judgment has to be made (of a target attribute) that is computationally complex, and instead a more easily calculated heuristic attribute is substituted. This substitution is thought of as taking place in the automatic intuitive judgment system, rather than the more self-aware reflective system.Kahneman, D., & Frederick, S. (2002). Representativeness revisited: Attribute substitution in intuitive judgment. In T. Gilovich, D. Griffin, & D. Kahneman (Eds.), Heuristics and Biases: The Psychology of Intuitive Judgment (pp. 49–81). Cambridge University Press. The availability heuristic (also known as the availability bias) is the tendency to overestimate the likelihood of events with greater "availability" in memory, which can be influenced by how recent the memories are or how unusual or emotionally charged they may be. There is a greater likelihood of recalling recent, nearby, or otherwise immediately available examples, and the imputation of importance to those examples over others. Conjunction fallacy, the tendency to assume that specific conditions are more probable than a more general version of those same conditions. Hot-cold empathy gap, the tendency to underestimate the influence of visceral drives on one's attitudes, preferences, and behaviors. Identifiable victim effect, people tend to be more persuaded by a story rather than a statistic or data set. Novelty bias, people have difficulty not seeking out the new and shiny thing. Tachypsychia: When time perceived by the individual either lengthens or contracts, making events appear to slow down or speed up. Time-saving bias, a tendency to underestimate the time that could be saved (or lost) when increasing (or decreasing) from a relatively low speed, and to overestimate the time that could be saved (or lost) when increasing (or decreasing) from a relatively high speed.Svenson, O. (2008). Decisions among time‑saving options: When intuition is strong and wrong. Acta Psychologica, 128(2), 187–197. https://doi.org/10.1016/j.actpsy.2007.12.005
Baseline The anchoring bias, or focalism, is the tendency to rely too heavily—to "anchor"—on one trait or piece of information when making decisions (usually the first piece of information acquired on that subject). Base rate fallacy or base rate neglect, the tendency to ignore general information and focus on information only pertaining to the specific case, even when the general information is more important. Dunning–Kruger effect, the tendency for unskilled individuals to overestimate their own ability and the tendency for experts to underestimate their own ability. Gambler's fallacy, the tendency to think that future probabilities are altered by past events, when in reality they are unchanged. The fallacy arises from an erroneous conceptualization of the law of large numbers. For example, "I've flipped heads with this coin five times consecutively, so the chance of tails coming out on the sixth flip is much greater than heads."Tversky, A., & Kahneman, D. (1971). Belief in the law of small numbers. Psychological Bulletin, 76(2), 105–110. https://doi.org/10.1037/h0031322 Hard–easy effect, the tendency to overestimate one's ability to accomplish hard tasks, and underestimate one's ability to accomplish easy tasks. Hot-hand fallacy (also known as "hot hand phenomenon" or "hot hand"), the belief that a person who has experienced success with a random event has a greater chance of further success in additional attempts.Gilovich, T., Vallone, R., & Tversky, A. (1985). The hot hand in basketball: On the misperception of random sequences. Cognitive Psychology, 17(3), 295–314. https://doi.org/10.1016/0010-0285(85)90010-6 Insensitivity to sample size, the tendency to under-expect variation in small samples. Interoceptive bias or hungry judge effect: The tendency for sensory input about the body itself to affect one's judgement about external, unrelated circumstances. (As for example, in parole judges who are more lenient when fed and rested.) or regressive bias: Tendency to remember high values and high likelihoods/probabilities/frequencies as lower than they actually were and low ones as higher than they actually were. Based on the evidence, memories are not extreme enough. Subadditivity effect: The tendency to estimate that the likelihood of a remembered event is less than the sum of its (more than two) mutually exclusive components. Systematic bias: Judgement that arises when targets of differentiating judgement become subject to effects of regression that are not equivalent. : The standard suggested amount of consumption (e.g., food serving size) is perceived to be appropriate, and a person would consume it all even if it is too much for this particular person."Penn Psychologists Believe 'Unit Bias' Determines The Acceptable Amount To Eat". ScienceDaily (November 21, 2005) Weber–Fechner law: Difficulty in perceiving and comparing small differences in large quantities.Fechner, G. T. (1860). Elemente der Psychophysik. Leipzig: Breitkopf & Härtel.
Inertia Conservatism bias, the tendency to insufficiently revise one's belief when presented with new evidence.
Outcome : The tendency to expect or predict more extreme outcomes than those outcomes that actually happen. Hedonic recall bias: The tendency for people who are satisfied with their wage to overestimate how much they earn, and conversely, for people who are unsatisfied with their wage to underestimate it. Illusion of validity, the tendency to overestimate the accuracy of one's judgments, especially when available information is consistent or inter-correlated. Impact bias: The tendency to overestimate the length or the intensity of the impact of future feeling states. Outcome bias: The tendency to judge a decision by its eventual outcome instead of the quality of the decision at the time it was made.Baron, J., & Hershey, J. C. (1988). Outcome bias in decision evaluation. Journal of Personality and Social Psychology, 54(4), 569–579. https://doi.org/10.1037/0022-3514.54.4.569 Planning fallacy, the tendency for people to underestimate the time it will take them to complete a given task. Restraint bias, the tendency to overestimate one's ability to show restraint in the face of temptation.Nordgren, L. F., van Harreveld, F., & van der Pligt, J. (2009). The restraint bias: How the illusion of self‑restraint promotes impulsive behavior. Psychological Science, 20(12), 1523–1528. https://doi.org/10.1111/j.1467-9280.2009.02468.x Sexual overperception bias, the tendency to overestimate sexual interest of another person in oneself, and sexual underperception bias, the tendency to underestimate it.Haselton, M. G. (2003). The sexual overperception bias: Evidence of a systematic bias in men's judgments of women's sexual interest. Journal of Research in Personality, 37(1), 34–47. https://doi.org/10.1016/S0092-6566(02)00510-7
Self-perspective Curse of knowledge: When better-informed people find it extremely difficult to think about problems from the perspective of lesser-informed people. Extrinsic incentives bias, an exception to the fundamental attribution error, where people view others as having (situational) extrinsic motivations, while viewing themselves as having (dispositional) intrinsic motivations.Ross, L., & Nisbett, R. E. (1991). The Person and the Situation: Perspectives of Social Psychology. McGraw-Hill. False consensus effect, the tendency for people to overestimate the degree to which others agree with them. Illusion of transparency, the tendency for people to overestimate the degree to which their personal mental state is known by others, and to overestimate how well they understand others' personal mental states.Gilovich, T., Savitsky, K., & Medvec, V. H. (1998). The illusion of transparency: Biased assessments of others' ability to read one's emotional states. Journal of Personality and Social Psychology, 75(2), 332–346. https://doi.org/10.1037/0022-3514.75.2.332 Naïve cynicism, expecting more egocentric bias in others than in oneself.Kruger, J., & Gilovich, T. (1999). Naive cynicism in everyday theories of responsibility assessment. Journal of Personality and Social Psychology, 76(5), 743–753. https://doi.org/10.1037/0022-3514.76.5.743 Optimism bias: The tendency to be over-optimistic, underestimating greatly the probability of undesirable outcomes and overestimating favorable and pleasing outcomes (see also wishful thinking, valence effect, positive outcome bias, and compare pessimism bias). Outgroup homogeneity bias, where individuals see members of other groups as being relatively less varied than members of their own group.